Remove the 'flags' argument from evdns_base_set_option() The 'flags' argument made sense when passed to evdns_(base_)?parse_resolv_conf when it said which parts of the resolv.conf file to obey. But for evdns_set_option(), it was really silly, since you wouldn't be calling evdns_set_option() unless you actually wanted to set the option. Its meaning was basically, "set this to DNS_OPTIONS_ALL unless you want a funny surprise." evdns_base_set_option was new in 2.0.1-alpha, so we aren't committed to keeping it source-compatible.